Unable to run programs in php

Hi , I have downloaded php-5.2.10-win32-installer.exe(18.6MB) and installed in my C:\php folder.at the time of installation i have clicked on apache 2.2.x(i have installed apache_2.2.11-win32-x86-openssl-0.9.8i also in C:\Apache Software Foundation\apache folder) and i have installed all the features of php which comes at the time of installation.after the installation ends i have create a .php file as below <?php echo " Hello php "; ?>                                 a very simple program to print hello php on the screen.i save this file as script.php in my desktop. after saving i cilck on it to run .there was some error something like Unable to locate component and in that message it says that some .dll files could not find .these dll files are OCI.dll , ntwdblib.dll etc. and it says to reinstall the php. but after reinstalling this problem occurs .                              one thing also that i have downloaded php-5.2.10-Win32.zip(10MB) also. when i install that zip file(after uncompress it but at this time i have not install the php-5.2.10-win32-installer.exe) my php programs will run good and display the output also. but after installing php-5.2.10-win32-installer.exe i can not run any php program.                             please help me. i am new in php.